This application is a 371 of PCT/US04/40032 filed on Nov. 29, 2004.
1. Technical Field
The present invention relates to antennas and more particularly to antenna couplers. Even more particularly, the invention relates to a quick check conformal antenna coupler which provides a reliable and repeatable RF interface between aircraft electronic countermeasure (ECM) system installations and flightline automated test equipment (ATE) without requiring the removal of aircraft radomes.
2. Background Information
Antenna couplers are devices used to match the impedance of a transmitter and/or receiver to an antenna to provide maximum power transfer. One of their uses is to provide the RF interface between an aircraft electronic countermeasure system (ECM) installation and flightline Automatic Test Equipment (ATE). Unlike most radar and communications systems, ECM systems typically operate over a wide range of frequencies, an octave or more is not uncommon. The interface must provide for a predictable and repeatable transfer function between the ATE and the System Under Test (SUT). Since this is an RF interface, the transfer function is described in terms of Voltage Standing Wave Ratio (VSWR), Insertion Loss (IL) and bandwidth (BW). Antenna couplers must also provide protection from interfering RF signals and security from disclosure of SUT performance parameters through unintentional broadcast of SUT/ATE emanations.
Antenna couplers for aircraft installed ECM Systems are required to perform “end to end” system testing. Antenna couplers have unique mechanical interfaces for each system antenna and antenna location. Antenna coupler sets are different for each aircraft type due to the physical differences between locations on different type aircraft. Also each aircraft generally will have a number of radar antennas protected by radomes, each of which heretofore had to be removed in order to perform the required tests requiring the use of relatively expensive and bulky test equipment. Also the locations of the radar antennas vary and are at locations, sometimes difficult to reach conveniently with such prior art heavy and bulky test equipment. Because of these design constraints existing antenna couplers are high cost items. Antenna couplers must also perform with high transmit power systems. Thus, antenna couplers for these applications tend to be rather large, expensive to use and maintain, and bulky to transport and store.
A need, therefore, exists for a low cost, compact size antenna coupler and a method for its production.